Some more comments and findings:
1) Upon looking closer at the values I cannot spot any differences between the values in the table and the values from your Autocad verification!!?? Where do you think are the values not same? It looks to me they are the same, at least up to the second decimal.
2) I notice that in your Autocad verification the lower Y value of the bounding box is -5.5 for all angles. This means you have designed the lower figure the same way as in the Mathcad sheet - point 3 in your list is always straight down. And as I have already written this in no way does not corrspond with the drawing you sent. Also it does not correspond with the title of the section where you name it "3/4 rectangular". This would be true in your drawing, but the way you created the points its a rectangle (+triangle) only for alpha=0, otherwise its just a parallelogram with no right angle!
3) According to the drawing, p.w should be only araound 2.2 (half the base at alpha=0) and not 5.5